package org.elasticsearch.index.analysis;

import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;

import java.io.IOException;
import java.io.Reader;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
public class STConvertTokenizer extends Tokenizer {

    private static final int DEFAULT_BUFFER_SIZE = 256;

    private boolean done = false;
    private int finalOffset;
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
    private String delimiter;
    private STConvertType convertType;
    private Boolean keepBoth;

    public STConvertTokenizer( STConvertType convertType,String delimiter,Boolean keepBoth) {
        this(DEFAULT_BUFFER_SIZE);
        this.delimiter = delimiter;
        this.convertType = convertType;
        this.keepBoth=keepBoth;
    }

    public STConvertTokenizer(int bufferSize) {
        super();
        termAtt.resizeBuffer(bufferSize);
    }

    @Override
    public final boolean incrementToken() throws IOException {
        if (!done) {
            clearAttributes();
            done = true;
            int upto = 0;
            char[] buffer = termAtt.buffer();
            while (true) {
                final int length = input.read(buffer, upto, buffer.length - upto);
                if (length == -1) break;
                upto += length;
                if (upto == buffer.length)
                    buffer = termAtt.resizeBuffer(1 + buffer.length);
            }
            termAtt.setLength(upto);
            String str = termAtt.toString();
            termAtt.setEmpty();
            String converted= STConverter.getInstance().convert(str, convertType);
            termAtt.append(converted);

            if(keepBoth){
                termAtt.append(delimiter);
                termAtt.append(str);
            }

            finalOffset = correctOffset(upto);
            offsetAtt.setOffset(correctOffset(0), finalOffset);
            return true;
        }
        return false;
    }

    @Override
    public final void end() {
        // set final offset
        offsetAtt.setOffset(finalOffset, finalOffset);
    }

    public void reset(Reader input) throws IOException {
        super.reset();
        this.done = false;
    }

    public void reset() throws IOException {
        super.reset();
        this.done = false;
    }


}
